Acid dyeing of polyamides using quaternary ammonium salts



States This invention relates to an improved process for dyeing polyamide textile materials, and particularly to a process for obtaining more level dyeings using selected acid dyes. This is a continuation-in-part of my copending application Serial No. 696,332, filed November 14, 1957, now abandoned.

Woven and knitted fabrics made from polyamide filaments such as taffeta and tricot fabrics exhibit severe barr or warp streaks when acid dyes are applied by normal procedures. Streaks are also encountered when acid dyes are applied to carpeting and upholstery made from textured polyamide filaments. One attempt to improve levelness and reduce the streak level employs swelling agents in the dye bath such as phenol, metacresol, ortho phenyl phenol, benzyl alcohol, and the like. These swelling agents are costly, have unpleasant odors, are often toxic and highly volatile, and are therefore not desirable for commercial dyeings. Another recent improvement in level dyeing of polyamides has been achieved by the use of anionic materials in the dye bath, such as sulfated fatty alcohols. However, these anionic materials present problems involving foaming and reduction of the number of available dye sites by blocking. At the same time, there has been an increasing demand in the market for washable garments made of polyamide filaments which require increased use of wash-fast acid dyes. In the case of carpeting and upholstery, there is a demand for the light fastness which can be obtained through use of selected acid dyes, particularly metallized dyes.

It is an object of this invention to reduce the streak level in polyamide dyeings employing acid dyestulfs, i.e. dye streaks in which varying amounts of color are absorbed by the yarn bundles. A further object is to provide a process for improving the uniformity of shade within a batch in multiple piece dyeings of polyamide filament fabrics. Other objects will be apparent from the description of the invention given below.

The above objects are accomplished in the dyeing of polyamide textile materials by the improvement which comprises carrying out the dyeing in an aqueous dye bath at pH of 2.5 to 3.5 in the presence of a small proportion of a quaternary ammonium salt of a long-chain fatty-acid polyester of a tetraalkylol alkylene diamine of the formula:

wherein R R R R and R are alkylene radicals of 2 to 6 carbon atoms each and wherein the number of ester groups is on the average not less than 1.5 and not more than 3.5 per molecule, and a small proportion of a polyoxyethylene which is a condensation product of l525 mols of ethylene oxide with 1 mol of a longchain fatty alcohol or mixture of fatty alcohols containing 12-18 carbon atoms.

The quaternary ammonium salts referred to above are described and claimed in Walter C. Meuly, U.S. application S.N. 591,266, filed June 14, 1956, to which reference is made for the preparation of said salts.

The quaternary ammonium salt is used in the dye bath in amounts of 0.257.5%. For taffeta and tricot fabrics a range of 0.5-1.5% based on the weight of the polyamide 7 3,25,l27 Patented Mar. 13, 1962 fiber is preferred, while for carpeting the higher concentration of about 3% to 6% based on polyamide is preferred. The condensation product of ethylene oxide and fatty alcohol is used in amounts in the range of 0.354.0%

based on the weight of the polyamide fiber. For taffeta and tricot fabrics a range of about 1.244% based on the weight of the polyamide fiber is preferred, while for carpeting a range of about 1.2 to about 4% is preferred. The two leveling agents are water soluble and may be prepared as a premixture and the premixed single agent added to the dye bath, usually in the form of an aqueous solution. Essentially the same results are obtained by using the premixture as by using the two agents added separately. However, the premixture offers some process advantages in the easier handling of materials. For best results, the ratio of condensation product to quaternary salt should be in the range of 0.4:1 to 2.421.

The conditions for dyeing the polyamide textiles in this invention are those normally used for these materials so that most dyeings will be carried out at temperatures of 180 F. to 250 F., the higher temperatures requiring the use of closed vessels and autogenous pressure. The aqueous dye bath must be adjusted to a pH of 2.53.5 for satisfactory dyeings. This pH range may be obtained by addition of small amounts of acid, formic acid and phosphoric acid being particularly preferred in concentrations of 23% based on the weight of the fiber.

The selection of dye for use in this invention is important in achieving optimum levelness and washfastness in the dyed polyamide garment fabrics. The best results have been obtained using monosulfonated acid dyes and relatively low molecular weight disulfonated acid dyes. Some improvement in levelness is also obtained by using certain milling acid dyes and direct dyes. Dye selection is also important in achieving optimum levelness and lightfastness in the dyed upholstery fabrics and carpeting. The best results are those obtained using metallized dyes, preferably neutral-dyeing premetallized acid dyes, i.e., those having a 2:1 azo dye molecule:metal atom structure, and derivatives of these dyes containing one or more sulfonic acid or sulfonamide groups. Preferably for dyeing carpeting, these neutral dyeing premetallized acid dyes will contain at least two sulfonic acid groups.

Normally, the dyes will be employed in amounts of 0.l%-5% based on the polyamide fiber weight, depending on the depth of shade desired. Examples of specific dyes, which when used singly or as mixtures produce level dyeings in accordance with this invention, together with their new Color Index No., include the following:

Dye New 0.1.

Acid Yellow 40 18, 950 Acid Yellow 34.-" 18, 890 Acid Yellow 11.--. 18, 820 Acid Yellow 17 18, 965 Direct Yellow 44 29,000 Cihalan" Brilliant Yellow 3GL Nylanthrene Yellow FLW Acid Orange 7 15, 510 Mordant Orange 6 26, 520 N ylanthrene Orange SLF Acid Red 66 26, 905 Acid Red 73 27. 290 Direct Red 37- 22, 240 Acid Red 6%, 215 Acid Red 1 18, 050 Acid Red 4- 14, 710 Nylanthrene Scarlet YLFW Benzyl Fast Red 2BL Xylene Fast Red P Acid Blue 45 63, 010 Acid Blue 47 62. 085 Acid Blue 78 62,105 Acid Blue 25 62, 055 Supernylitc Blue B Acid Violet 43-- 60, 730 Acid Blue 67 Acid Green 25. 61, 570

For best results, selection should be made with respect to dyes used and ratio of the condensation product to quaternary salt. For example, when dyeing carpeting with metallized dyes containing no sulfonic acid groups, which may or may not contain sulfonamide groups, the ratio of the condensation product to the quaternary salt will be 0.4:1 for optimum effect. When using the metallized dyes containing one or more sulfonic acid groups and when using direct dyes, the preferred ratio is 1.7:1. With non-metallized sulfonic acid-containing wool dyes for dyeing carpeting, the preferred ratio is within a range of 1.7:1 to 0.4:1.

On the other hand when dyeing polyamide fibers other than carpeting and upholstery fabrics, the ratio of condensation product to quaternary compound is preferably 1.5:1 to 2:1.

After selecting the dyestufr' preferred for a particular fabric, the proportion of nonionic to cationic material, dyeing temperature and pH, within the specified range, may readily be selected for optimum results.

The process of this invention may be employed for dyeing all types of polyamide textile materials i.e., those materials containing at least about 25% by weight of polyamide, such as fibers and filaments, yarns, skeins, woven and knitted fabrics such as taffetas and tricots, non-woven batts, and the like. However, this invention is particularly singular for dyeing polyamide filament fabrics of the taffeta and tricot types. When dyeing upholstery and carpeting of bulked filament yarns, it is particularly advantageous to use neutral dyeing metallized dyes as discussed above. Within this group of suitable dyes, there are included: sulfonamide dyes, such as the metallized dye formed from Color Index base 12,160 by demethylation and formation of the 1:2 chromium complex, and sulfonic acid types, such as 1:2 chromium complex of Color Index based 14,640, 1:2 chromium complex of Color Index base, 18,730, 1:2 chromium complex of Color Index base 15,710.

The polyamide filamentous materials employed in preparing the above textiles may be composed of polyhexamethylene adipamide, polyhexamethylene sebaeamide, polycaproamide, and copolyamides of the above, and other polyamides based on products derived by the condensation of diamines with dibasic acids to give fiber- -forming superpolymers.

The chief advantage of this invention is the provision of a process which permits the application of selected dyes to polyamide textiles to yield good washfastness and/or light-fastness, uniformity of shade and lack of dye streaks. The dyeings achieved in this invention are superior in lack of streakiness to those heretofore possible by other dyeing methods such as anionic assisted dyeings, especially at practical dyeing temperatures of 180 F.212 F., without resorting to pressure dyeings. In particular, this invention yields better dispersion of the complex dye than other similar dyeing processes and even uses less leveling agent in many cases. Furthermore, this invention does not cause foaming difi iculties normally associated with anionic assisted dyeings. An additional advantage is the fact that a level dyeing and a soft hand of garment fabric are obtained simultaneously without the customary addition of softening agents which normally requires an extra finishing step.

The following examples illustrate specific embodiments of the invention without limiting the scope thereof. All parts and percentages are by weight, unless otherwise specified.

The quaternary ammonium salt used in the examples was prepared according to Example 6 of Meuly U.S. Ser. No. 591,266, wherein N-(Z-hydroxyethyl)-N,N',N-tris(2- hydroxypropyl)-ethylene diamine (1 mole) was esterified with oleic acid (2 moles) to give a liquid long-chain fatty-acid polyester, which in turn was quaternized 'with dimethyl sulfate (0.9 mole) to form the liquid quaternary ammonium salt of the polyester. The condensation product used in the examples was prepared by the condensation of about 20 moles of ethylene oxide with one mole of a mixture of long-chain fatty alcohols containing principally C and C alcohols, approximately 50% of said Samples of a commercial tricot fabric knitted of polyhexamethylene adipamide continuous filament yarn (40 denier, 13 filament) were dyed at two temperatures to compare the relative levelness obtained by different dyeing methods. The dye used was a mixture of 0.4% Nylanthrene Scarlet YLFW and 0.25% Acid Yellow 40, the amounts being by weight based on the weight of fiber. Using the process of this invention, the aqueous dye bath was set at 120 F., then the quaternary salt and the condensation product were added (separately in one run, and as a premix in another run) in the amounts given in Table I, based on the weight of fiber in the dye bath. 2% formic acid was added to bring the pH to 3.5 Then the dyes were added and the temperature of the bath raised to the point indicated in the table and the dyeing allowed to proceed for minutes. A comparative dyeing was made with a similar sample of the tricot fabric using the anionic leveling agent described above by setting the dye bath at room temperature, adding the indicated amount of anionic agent, then the same amount of dyes, and finally 0.5% acetic acid based on the weight of fiber. The dye bath temperature was then raised to the indicated point and the dyeing carried out for 30 minutes. Then 0.5% more acetic acid was added and the dyeing continued for an additional 60 minutes. A control dyeing was carried out under the latter conditions except no leveling agent was used. Each fabric was given a levelness rating by visual appearance based on the uniformity of shade of the dyeing and the presence or lack of streaks on a scale of 1 to 10, from poor to excellent, a rating of 7 being of questionable acceptability because of some noticeable barr streaks. The levelness ratings listed in Table I show the superiority of the dyeings made in accordance with this invention, regardless of whether the leveling agents are added separately or as a single premix to the dye bath, over comparative dyeings made in the presence of a typical anionic agent.

A series of dyeings was carried out on samples of the same polyamide tricot fabric of Example I, using the same combination of two leveling agents of this invention as in Example I (added to the dye bath as a premixture of the two agents), and for comparison another series of dyeings was carried out using the same anionic leveling agent of Example I. The leveling agents or agent were added to the aqueous dye bath in the amounts specified based on the weight of fiber, and formic acid was added to bring the pH to 3.5. Then the indicated dye was added in amounts of 0.5% based on the fiber weight, and the temperature of the dye bath was raised to 205 F. The fabrics were dyed at this temperature for 90 minutes. Each dyed fabric was given a visual levelness rating by the same scale as in Example I. The ratings shown in Table II indicate the excellent uniformity and levelness of the dyeings prepared according to this invention.

Table 11 Level- Dye Leveling agent ness rating Benzyl Fast Red 2BL 2% anionic 8 Do 3.5% premix of 2.25% nd.

prloduct and 1.25% quaternary sa 1;. Acid Blue 67 2% anionic 8 Do 3.5% premix of 2.25% 00nd. 10

prloduct and 1.25% quaternary sa t.

EXAMPLE III A batch of 10 pieces of the same polyamide tricot fabric as that of Example I (total fabric weight=342 lbs.) was dyed red with a premixture of the same two leveling agents used in Example I according to the teachings of this invention. The aqueous dye bath was set at 120 F. and 2.8% of the premix of the two leveling agents added (1.8% condensation product and 1% quaternary ammonium salt by weight of the total fabric) together with the 10 pieces of fabric. This mixture was agitated for 10 minutes. 3% formic acid based on the fabric was then added to give the dye bath a pH of 3.0-3.5, and the bath agitated for 10 minutes more. Then the following dyes were added in the specified amounts based on the fabric weight:

0.765% Acid Red 4 0.260% Acid Red 80 0.130% Acid Yellow 11 The bath temperature was raised to 205 F. in 40 minutes and the contents dyed for 60 minutes. Then 0.22% more Acid Red 4 and 0.07% more Acid Yellow 11 were added and the dyeing continued 30 minutes longer. Then 0.09% more Acid Red 80 was added and the dyeing continued for an additional 30 minutes. The fabrics were then rinsed. Five pieces were treated during finishing with a commercial softening agent, and no additional finishing agent was applied to the other five pieces. Using the same visual levelness ratings as in the previous examples, it was found that all ten pieces of fabric were satisfactory both in the levelness of the dyeing as well as the coverage of barr streaks. The five pieces that were not treated with an additional finishing agent were equally soft and possessed a slightly more desirable (i.e., drier) hand than the five pieces that were treated with the additional commercial finishing agent. When a control dyeing is run on the same fabric without the presence of the two leveling agents, the result is a red fabric having many visible and objectionable streaks, said fabric being unsatisfactory for commercial use.

In the following examples, percentages are based on the total weight of fabric.

EXAMPLE IV A cotton-rayon backed upholstery fabric (12 lbs. total weight) having a face of bulked nylon filament yarn (33 %-rnade in accordance with the teachings of Breen and Lauterbach in US. application S.N. 772,475, filed November 7, 195 8) in which the backing had previously been dyed with direct dyes by conventional procedure, was treated in a fresh bath with neutral-dyeing premetallized dyes to color the nylon face. This dyebath at 40:1 liquor to goods ratio, was set at 90 F. and there was added 1.5% of the quaternary salt, 0.6% of the condensation product-and 2.0% phosphoric acid (85%). The goods were treated for 10 minutes, then there was added 0.22% of the 1:2 cobalt complex of Color Index base 15,675 and 0.46% of the dye described in Example II of French Patent 1,159,779. The dyeing was run 10 minutes at 90 F., the pH adjusted to 2.8, the

0 temperature raised to 160 F. over 30 minutes, then to 212 F. over one hour; the goods were dyed for 30 minutes at 212 F., sampled, cooled, rinsed at 140 F. for 10 minutes, the bath was dropped, the fabric extracted and dried at 250 F The levelness of the dyed upholstery was very satisfactory, whereas, a similar fabric dyed in a similar manner except for the substitution of the sodium lauryl sulfate anionic leveling agent for the quaternary salt/ nonionic blend, exhibited a severe, streaky-dyed condition which was unacceptable in levelness.

EXAMPLE V A sample of tufted carpet (100 grams) consisting of a jute backing (35%) and a bulked, continuous filament polyhexamethylene adip-amide yarn facing (65 %made in accordance with the teachings of Breen and Lanterbach in US. application S.N. 772,475) was dyed as follows: The aqueous dye bath was set at F., then 4.0% of a premix of 1 part of the quaternary salt to 1.7 parts of the condensation product was added (based on the total weight of the carpet) in the dye bath. This premix consists of 25% by weight quaternary salt, 42.5% condensation product and 32.5% inert diluents. The volume of the dyebath was 3500 cc. Three percent formic acid was added to bring the pH to 3.0. Then 0.25% of Direct Red I (Color Index 22,310) was added and the temperature of the bath raised to 205 F. and dyeing continued for 60 minutes. A visual examination of the dyeing was made and it was found to be very level. A control dyeing made without the mixture of the quaternary salt and the condensation product was very unlevel.

Dyeing as above using the above premix at pH levels of 1.2 and 5.0 gave unlevel dyeing results.

EXAMPLE VI Example V was repeated but using a disulfonated metallized dye, which is prepared by forming a chromium complex from one chromium atom and two moles of the azo color base defined by the formula:

(.FH N=NC=CITI some N i 01 0H The dyeing gave excellent coverage of streaks on the tufted carpet.

EXAMPLE VII Example VI was repeated using a monosulfonated metallized dye which is prepared by forming a chromium complex having one chromium atom with an equimolar mixture of each of the following two azo color bases:

The dyeing resulted in good coverage of streaks on the carpet.

EXAMPLE IX The general procedure of Example V was repeated using as the dye C.I. Acid Green 25 and using 2.5 parts of the quaternary salt and l pant of the condensation product. This dyeing covered adjacent yarns having approximately 35% to 40% differences in dye intensity after dyeing in the absence of the quaternary salt and condensation product according to normal dyeing procedures and was considered a very marked improvement.

In place of the particular qua-ternary salt used in the examples there may also be employed the salts obtained from quaternizing the reaction products from the esterification of 1 mole of N,N,N,N' tetrakis-(Z-hydroxypropyl)-ethylene diamine with 3 moles of stearic acid, or 1 mole of N,N,N,N-tetrakis-(2 hydroxypropyl)- ethylene diamine with 2.1 moles of oleic acid, or 1 mole of N,N,N,N tetrakis-(2-hydroxyethyl)-ethylene diamine with 2 moles of stearic acid, or 1 mole of N-(Z-hydroxyethyl) -N,N',N'ltI-1S( 2-hydroxypropyl) ethylene diamine with 1.9 moles of oleic acid, or 1 mole of N,N,N,N- tetrakis-(2-hydroxypropyl)-ethylene diamine with 2.2 moles of l'auric acid, or the like. Also in place of the particular polyoxyethylene condensation product used in the examples there may be used other similar polyoxyethylenes such as those prepared by reacting 18 moles of ethylene oxide with 1 mole of a mixture of longchain fatty alcohols containing principally C C and C alcohols, 25% of which are unsaturated alcohols, or those obtained by reacting 20 moles of ethylene oxide with one mole of a mixture of 75% oleyl alcohol and 25% stearyl alcohol, or those obtained by reacting 25 moles of ethylene oxide with one mole of a mixture of about 50% C saturated fatty alcohol, about 25% C unsaturated fatty alcohol and about 25% C unsaturated fatty alcohol, or the like.

The use of organic carriers (e.g., orthophenyl phenol, benzoic acid, meta-cresol, diphenyl, chlorobenzene, benzaldehyde, para cymene, and tetrahydronaphthalene) as a pretreatment of the polyamide textile before dyeing or in the dye bath during the dyeing process of this invention tends to improve the evenness of the dyed goods compared with the results obtained in the absence of carriers.

I claim:

1. A process of preparing an aqueous dye bath for polyamide textile materials, said process comprising the steps of: adding a quaternary ammonium salt of a longchain fatty-acid polyester of a tetraalkylol alkylene diamine of the formula:

HO-Rz R -OH NR1-N HO-R4 Rr-OH wherein R R R R and R are alkylene radicals of 2 to 6 carbon atoms each and wherein the number of ester groups is on the average not less than 1.5 and not more than 3.5 per molecule and a polyoxyethylene which is a condensation product of 15-25 mols of ethylene oxide with 1 mol of long-chain fatty alcohol containing 12-18 carbon atoms to the dye bath, the total addition being less than by weight of the materials to be dyed, the ratio of condensation product to quaternary ammonium salt being in the range of from 0.411 to 2.4: 1; adjusting the acidity of the bath to a pH of from 2.5-

3.5; adding from 0.1-5 by weight of an acid dye, based on the weight of said materials; and heating the bath to a temperature of no more than 212 F.

2. A process of dyeing polyamide textile materials in an aqueous dye bath, said process comprising the steps of: adding a quaternary ammonium salt of a long-chain fatty-acid polyester of a tetraalkylol alkylene diamine of the formula:

HOR4 \R5OH wherein R R R R and R are alkylene radicals of 2 to 6 carbon atoms each and wherein the number of ester groups is on the average not less than 1.5 and not more than 3.5 per molecule and a polyoxyethylene which is a condensation product of 15-25 mols of ethylene oxide with 1 mol of long-chain fatty alcohol containing 12- 18 carbon atoms to the dye bath, the total addition being less than 10% by weight of the materials to be dyed, the ratio of condensation product to quaternary ammonium salt being in the range of from 0.4:1 to 2.421; adjusting the acidity of the bath to a pH of from 2.5-3.5; adding from 0.1-5% by weight of an acid dye, based on the weight of said materials; heating the bath to a temperature of no more than 212 F.; and dyeing said materials in the bath.

3. The process of claim 2 in which the dye is a mono sulfonated acid dye.

4. The process of claim 2 in which the quaternary ammonium salt is present in the amount of from 0.25% to 7.5% based on the weight of the polyamide textile material.

5. The process of claim 2 in. which the quaternary ammonium salt is present in the amount of from 0.5% to 1.5% based on the weight of the polyamide textile material.

6. The process of claim 2 in which the quaternary ammonium salt is obtained by reacting about 0.9 mol of dimethyl sulfate with the esterification product of about 1 mol of N-(2-hydroxyethyl)-N,N',N'-tris(2-hydroxypropyl)-ethylene diamine with 2 mols of oleic acid and the said polyoxyethylene is the condensation product of about 20 mols of ethylene oxide with 1 mol of a mixture of long-chain fatty alcohols containing principally C and C alcohols, approximately 50% of the mixture being unsaturated alcohols.

7. A leveling agent consisting essentially of a quaternary ammonium salt of a long-chain fatty-acid polyester of a tetraalkylol alkylene diamine of the formula:

wherein R R R R and R are alkylene radicals of '2 to 6 carbon atoms each and wherein the number of References Cited in the file of this patent UNITED STATES PATENTS Schoeller et a1. Aug. 21, 1934 Conbere et a1. Mar. 17, 1959 OTHER REFERENCES Hadfield et al.: J.S.D'.C., December 1948, p. 382.

Schwartz et al.: Surface Active Agents and Detergents, vol. II, pages 266-268, 272.

Dupont: The Technical Bulletin, vol. 10, No. 1, March 1954, pp. 32-37.

Silk Journal and Rayon World, July 1944, pp. 36-38. 

2. A PROCESS OF DYEING POLYAMIDE TEXTILE MATERIALS IN AN AQUEOUS DYE, BATH SAID PROCESS COMPRISING THE STEPS OF: ADDING A QUATERNARY AMMONIUM SALT OF A LONG-CHAIN FATTY-ACID POLYESTER OF A TETRAALKYLOL ALKYLENE DIAMINE OF THE FORMULA: 